Brake booster, and method and device for the operation thereof

Abstract

A controllable brake booster and a method and a device for controlling the brake booster are disclosed. The pedal force that a driver must apply in order to convey an input element of the brake booster into an actuating position or to retain the element in an actuating position is adjusted by operating the brake booster.

The invention claimed is: 
     
       1. A method for operating a controllable brake booster of a brake system of a motor vehicle, comprising:
 using an input element of the controllable brake booster to activate the brake system, 
 wherein a pedal force which acts on the input element is set by operating the controllable brake booster, and wherein a first spring element is arranged between the input element and a booster body of the controllable brake booster, and further wherein a second spring element is arranged between an output element of the controllable brake booster and a master cylinder, 
 wherein the pedal force depends on an effect of the first and/or second spring element and is set by the brake booster using at least one piece of information in relation to the first and/or second effect. 
 
     
     
       2. The method as claimed in  claim 1 , wherein an idle travel dependent on an operating mode of the brake booster is provided between the input element and the output element, further comprising:
 when an idle travel is present, operating the controllable brake booster to apply a supporting force correlating to a displacement travel of the input element. 
 
     
     
       3. The method as claimed in  claim 2 , wherein the pedal force is dependent on the effect of the first spring element. 
     
     
       4. The method as claimed in  claim 3 , wherein the pedal force is dependent on the effect of the first spring element via a spring force according to the correlation: the pedal force=the spring force. 
     
     
       5. The method as claimed in  claim 1 , wherein an idle travel dependent on the operating mode of the brake booster is provided between the input element and the output element, and wherein the brake booster is configured to apply a supporting force acting on the output element, further comprising:
 when the idle travel is overcome, operating the controllable brake booster such that the pedal force is set by adjusting the supporting force. 
 
     
     
       6. The method as claimed in  claim 5 , wherein the supporting force is set by operating the brake booster such that the pedal force acting on the input element assumes a pre-specified value. 
     
     
       7. The method as claimed in  claim 6 , wherein the pre-specified value for the pedal force depends on a displacement travel of the input element. 
     
     
       8. The method as claimed in  claim 6 , wherein the pre-specified value for the pedal force depends on the effect of the first spring element, the effect of the second spring element called the second spring force, and on he supporting force according to the correlation: the pedal force=a first spring force+the second spring force+an additional force—the supporting force, and is set using at least one piece of information relating to these values. 
     
     
       9. The method as claimed in  claim 8 , wherein:
 when the only braking effect is applied by an additional brake system, adjusting the supporting force each pedal force is less than or equal to a limit value of the pedal force on the input element, and 
 the limit value of the pedal force on the input element arises according to the following formula: the limit value of the pedal force on the input element=the first spring force+the second spring force. 
 
     
     
       10. The method as claimed in  claim 6 , wherein the pre-specified value for the pedal force depends on a displacement travel of the input element in the form of a curve. 
     
     
       11. The method as claimed in  claim 1 , wherein (i) the controllable brake booster is part of a hydraulic partial brake system of a total brake system, (ii) the total brake system as well as the hydraulic partial brake system has an additional partial brake system, and (iii) the brake booster is configured to apply a supporting force that acts on the output element, further comprising:
 countering a change in the pedal force by adjusting the supporting force, and 
 initiating the change in the pedal force by adapting a braking effect of the hydraulic partial brake system to a change in braking effect of the additional partial brake system. 
 
     
     
       12. The method as claimed in  claim 11 , wherein the braking effect is adapted such that a total braking effect of the hydraulic partial brake system and the additional partial brake system is held constant. 
     
     
       13. The method as claimed in  claim 11 , wherein the braking effect of the hydraulic partial brake system is adapted by setting the braking effect independently of the driver's force by an adaptation device. 
     
     
       14. A device for controlling a controllable brake booster which is part of a brake system of a motor vehicle, comprising:
 an input element configured to activate the brake system, wherein the controllable brake booster is configured to apply a supporting force that acts on an output element of the brake booster, and wherein the control takes place such that by the brake booster a pedal force is set which acts on the input element, 
 a first spring element arranged between the input element and a booster body of the controllable brake booster, and 
 a second spring element arranged between the output element of the controllable brake booster and a master cylinder, 
 wherein the control by the brake booster takes place such that the pedal force depends on an effect of the first and/or second spring element. 
 
     
     
       15. The device as claimed in  claim 14 , wherein:
 an idle travel dependent on an operating mode of the brake booster is provided between the input element and the output element, and 
 the control takes place such that when the idle travel is overcome, the controllable brake booster applies the supporting force by which the pedal force is set. 
 
     
     
       16. The device as claimed in  claim 15 , wherein:
 the controllable brake booster is part of a hydraulic partial brake system of a total brake system which as well as the hydraulic partial brake system has an additional partial brake system, 
 the control takes place such that the brake booster applies the supporting force which counters a change in the pedal force, and 
 the change in the pedal force is initiated by adapting a braking effect of the hydraulic partial brake system to a change in a braking effect of the additional partial brake system.